You have a 1964 Washington Quarter, minted at the Philadelphia mint, which falls within the United States coinage series. This particular coin is notable for being a special production, often desirable among collectors. It belongs to the denomination of 25 cents or a quarter, and features a diameter of 24.3 mm and a weight of 6.25 grams. The coin's composition is silver, contributing to its appeal and intrinsic value. Notably, it bears the 'P' mint mark, indicating it was produced in Philadelphia. With a mintage of 0, this specific piece could potentially signify something unique or a special collectible edition, as there is no recorded circulation or production for this year. Overall, as a part of the Washington Quarters series, the 1964 coin is not just a piece of currency but a historical artifact representing a significant era in American coinage. Whether you're a seasoned numismatist or a casual collector, this quarter holds both aesthetic and collectible value in the realm of silver coins.